#!/bin/bash

#double loop

read -p "please input the first number : " nu  
read -p "please input the second number : " mu

s=0

for ((j=1;j<=$mu;j++))
do
		for ((i=1;i<=$nu;i++))
		do
			s=$(($s+$i))
		done
done

echo "The result of '1+2..$nu' is ==> $s"
